1. Field of the Invention
The present invention relates to a cage shaped-polyhedral organosilicon compound having organofluoro groups (perfluoroalkyl groups), or organofluoro groups and reactive functional groups and to a method for producing the same, and to a material for forming a film comprising the polyhedral organosilicon compound and to a film formed using the material for forming a film comprising the polyhedral organosilicon compound. The polyhedral organosilicon compound of the present invention is useful as a material for forming a film which enables one to employ any one of a dry method or a wet method for forming a film. The organosilicon compound has a low dielectric constant and refractive index and exhibits water and oil repellency. Using the organosilicon compound, patterning can be done and a film having a high hardness can be provided which has excellent heat resistance and fire resistance.
2. Description of the Background
Polyorganosiloxanes are polymers in which organic groups are bonded to silicon having a siloxane bond structure. The polymers have excellent thermal properties such as heat resistance and cold resistance, as well as repellent surface properties. Polyorganosiloxanes have been used in various fields of application in the form of silicone resins, rubbers, oils and the like. Structural units of polyorganosiloxanes comprise four types, from one functionality to four functionalties. Polyorganosiloxane compounds are formed which have a chain structure, a cyclic structure, a cage structure or a three-dimensional network structure corresponding to the various structural units. Of these compounds, compounds having the cage structure comprise a structural unit of three functionalities (RSiO.sub.3/2) and is called as (poly)silsesquioxane. The compounds are expected to be used in various ways including new uses since the compounds have properties different from those of polymers which comprise a single compound.
In general, the above-mentioned (poly)silsesquioxane is prepared by hydrolysis and dehydration-condensation of silane monomers. In the case of using the (poly)silsesquioxane to form a film, it is possible to change film properties by changing the composition of alkyl groups remaining after hydrolysis or by introducing various substituents into the alkyl groups.
Accordingly, a possibility is to use a (poly)silsesquioxane in various ways, more than for the preparation of inorganic silica films which are prepared from four-functional silane monomers. For example, a film having water and oil repellency, which properties are attributable to organofluoro groups, can be prepared from (poly)silsesquioxanes bearing fluoroalkyl groups.
However, the materials which are used for the formation of a film are synthesized from three-functional group containing silane monomers containing organofluoro groups by conventional methods. The materials can not compose macromolecules with the result that the films obtained from the materials exhibit a low hardness and can not be put to practical use. In addition, the films prepared exhibit low water stability and have problems such as denaturation and precipitation during storage. Polymers comprising these materials have not been used as film-forming materials.
Polymers containing fluorine such as poly(tetrafluoroethylene) are conventionally used as materials which impart water and oil repellency to the surfaces of substrate materials. However, these kinds of polymers have a problem in that it is difficult to use them as film-forming materials, since the polymers are not sufficiently adhesive to substrates and have low solubility in organic solvents.